A resveratrol-loaded nanostructured lipid carrier hydrogel to enhance the anti-UV irradiation and anti-oxidant efficacy

Scheme 1. Schematic illustration of preparation and anti-UV irradiation as well as anti-oxidant efficacy of RES-NLC-gel. [Display omitted] •RES-NLC-gel improved the stability of RES under ultraviolet irradiation.•RES-NLC-gel significantly increased the accumulation of RES in the epidermis.•RES-NLC-gel showed safety in topical application.•RES-NLC-gel exhibited excellent anti-UV irradiation and anti-oxidative activity in vitro and in vivo. Exposure to ultraviolet (UV) irradiation leads to the generation of reactive oxygen species (ROS) and DNA damage in skin tissue, which can further result in skin cancers. Using sunscreens is one of the most popular and the most effective method to resist UV irradiation. Resveratrol (RES) shows high absorbance in UV region and significant anti-oxidant effects. However, RES is easily degraded by UV irradiation, resulting in the decrease of bioactivity and the limitation of its application in the pharmaceutical preparations of skin. In this paper, a nanostructured lipid carrier gel loaded with RES (RES-NLC-gel) was prepared to improve the stability of RES and the accumulation of RES in the epidermis. Moreover, RES-NLC-gel could scavenge free radical effectively and protect human keratinocyte from UV irradiation by inhibiting the generation of ROS, decreasing the protein expression of cleaved caspase-3 and Bax and increasing the protein expression of Bcl-2. When mice skin was pretreated with RES-NLC-gel, there were less erythema, wrinkles and scabs on mice skin. The epidermal thickness of mice skins obviously reduced in dose-dependent manner. The activities of catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) in mice skin tissue significantly increased. Thus, RES-NLC-gel exhibited an obvious anti-UV irradiation and anti-oxidant activity in vivo. RES-NLC-gel displayed great application potential in protecting skin from UV irradiation.